<?php


/**
 * Core_DB 
 *  数据库操作类
 * @package DB.class.php
 * @version $id$
 * @copyright blankyao
 * @author blankyao <blankyao@gmail.com> 
 * @license PHP Version 3.0 {@link http://www.php.net/license/3_0.txt}
 * @todo 对分页的支持
 */
class Core_DB {

    var $version = '';
    var $querynum = 0;
    var $link;
    var $halt;

    function connect($dbhost, $dbuser, $dbpw, $dbname = '', $pconnect = 0, $halt = TRUE, $dbcharset2 = '') {
        $this->halt = $halt;
        $func = empty($pconnect) ? 'mysql_connect' : 'mysql_pconnect';
        if(!$this->link = @$func($dbhost, $dbuser, $dbpw, 1)) {
            $halt && $this->halt('Can not connect to MySQL server');
        } else {
            if($this->version() > '4.1') {
                global $charset, $dbcharset;
                $dbcharset = $dbcharset2 ? $dbcharset2 : $dbcharset;
                $dbcharset = !$dbcharset && in_array(strtolower($charset), array('gbk', 'big5', 'utf-8')) ? str_replace('-', '', $charset) : $dbcharset;
                $serverset = $dbcharset ? 'character_set_connection='.$dbcharset.', character_set_results='.$dbcharset.', character_set_client=binary' : '';
                $serverset .= $this->version() > '5.0.1' ? ((empty($serverset) ? '' : ',').'sql_mode=\'\'') : '';
                $serverset && mysql_query("SET $serverset", $this->link);
            }
            if($dbname) {
                if(!mysql_select_db($dbname, $this->link) && $halt) {
                    $this->halt($this->error(), $this->errno());
                }
            }
        }

    }

    function selectDb($dbname) {
        return mysql_select_db($dbname, $this->link);
    }

    function fetchArray($query, $result_type = MYSQL_ASSOC) {
        return mysql_fetch_array($query, $result_type);
    }

    function fetchFirst($sql) {
        return $this->fetchArray($this->query($sql));
    }

    function resultFirst($sql) {
        return $this->result($this->query($sql), 0);
    }

    function query($sql, $type = '') {
        $func = $type == 'UNBUFFERED' && @function_exists('mysql_unbuffered_query') ?
            'mysql_unbuffered_query' : 'mysql_query';
        if(!($query = $func($sql, $this->link)) && $this->halt) {
            $this->halt($this->error(), $this->errno());
        }

        $this->querynum++;
        return $query;
    }

    function affectedRows() {
        return mysql_affected_rows($this->link);
    }

    function error() {
        return (($this->link) ? mysql_error($this->link) : mysql_error());
    }

    function errno() {
        return intval(($this->link) ? mysql_errno($this->link) : mysql_errno());
    }

    function result($query, $row = 0) {
        $query = @mysql_result($query, $row);
        return $query;
    }

    function numRows($query) {
        $query = mysql_num_rows($query);
        return $query;
    }

    function numFields($query) {
        return mysql_num_fields($query);
    }

    function freeResult($query) {
        return mysql_free_result($query);
    }

    function insertId() {
        return ($id = mysql_insert_id($this->link)) >= 0 ? $id : $this->result($this->query("SELECT last_insert_id()"), 0);
    }

    function fetchRow($query) {
        $query = mysql_fetch_row($query);
        return $query;
    }

    function fetchFields($query) {
        return mysql_fetch_field($query);
    }

    function version() {
        if(empty($this->version)) {
            $this->version = mysql_get_server_info($this->link);
        }
        return $this->version;
    }

    function close() {
        return mysql_close($this->link);
    }

    function halt($message = '', $errno = '') {
        throw new Core_Exception($message, $errno);
    }
}
?>
